Gripper.



A. G. SPENCER.

GRIPPER.

APPLICATION FILED AUG.15. 1907.

Patented Aug. 29, 1911.

Fig. 1.

W/TA/ESSES.

MQS

UNT SAT ATNT FFTQE.

ALVAI-I C. SPENCER, OF BEVERLY, MASSACHUSETTS, ASSIGNOR T0 UNITED SHOEMACHINERY COMPANY, OF PATERSON, NEW JERSEY, A. CORPORATION OF NEWJERSEY.

GRIPPER.

Specification of Letters Patent.

Patented Aug. 29, 1911.

To all whom it may concern:

, Be it known that I, ALVAI-I C. SPENCER, a citizen of the UnitedStates, residing at Beverly, in the county of Essex and Commonwealth ofMassachusetts, have invented certain Improvements in Grippers, of whichthe following description, in connection with the accompanying drawings,is a specification, like reference characters on the drawings indicatinglike parts in the several figures.

This invention relates to apparatus for use in the manufacture of bootsand shoes and particularly to grippers employed for working a shoe upperover a last. These grippers usually comprise one rigidly mounted jaw anda cooperating'relatively movable jaw by which the upper is gripped andthen pulled to strain it about the last and conform it to the contour ofthe last, These gripper jaws are subjected to severe strains which tendto cause the connections between the parts to work loose. Particularlyis this difliculty found with the connection of the rigid jaw with itsmounting. Looseness of this jaw is very objectionable because it notonly tends to render the grip of the jaws upon the stock insecure but anexcessive movement of the cooperating jaw is required to compensate forthe looseness of the normally rigid jaw and thus an extra force isusually applied for actuating the other jaw in an endeavor to minimizethe insecurity of the grip on the upper and this causes otherconnections to wear rapidly and soon become loose.

An important object of this invention is to provide an improvedconstruction of grippers by which the rigid jaw is held more securelythan heretofore so that the gripper stock may beheld more firmly and theexcessive straining of other parts of the grippers and the consequentwear upon them is avoided.

To this end a feature of the invention consists in a gripper mechanismcomprising a casing formed to receive the shank of a gripper jaw andprovided with alined recesses adapted to receive a holding member. Oneof the recesses is tapered to receive a wedge shaped locking memberwhich has operative engagement with the holding member and is soconstructed and arranged that when it is forced into said taperingrecess it will clamp the casing upon the shank of the gripper jaw andwill be automatically locked in adjusted position with relation to theholding member.

In the preferred embodiment of the invention the recess which receivesthe locking member is tapered from its outer larger end inwardly and thelocking member has screw threaded engagement with the holding member andis slotted or divided. By rotating the two members relatively thelocking member may be drawn into the tapering recess, clamping thecasing against the shank of the gripper jaw, and at the same time willbe compressed circumferentially and caused to grip and lock itself uponthe holding member so as to retain its position thereon. For preventingthe holding member from rotary movement during the use of the gripperssaid member is provided with a tapering portion which engages walls thatare inclined oppositely to the walls of the recess which receives thelocking member. The tapering recesses which receive the locking memberand the tapering portion of the holding member are preferably formed inresilient edge plates which extend downward from the grippers casing,and when these edge plates are drawn together by the two members toclamp the shank of the gripper jaw they react upon the tapering parts ofthe holding and locking members and cause them to be tightly wedgedtogether, and prevent relative rotation of the two members and hence theworking loose of the parts.

The invention will be more fully ex plained in the following descriptionof the preferred embodiment thereof and will be pointed out in theclaims.

Figure l is a side elevation, partly in section, of grippers embodyingthis invention; Fig. 2 is a section 011 line 22 of Fig. 1; Fig. 3 is asection on line 33 of Figs. 1 and 2 on a larger scale; Fig. 4 is adetail; Fig. 5 is a modification.

The gripper mechanism comprises an operating bar 2 movable lengthwise intwo complemental casings at, 1 containing gripper controlling devices 6,6 to which the bar is detachably connected by a hook 8 which may bedisengaged from the controlling devices by a tripper 10. Eachcontrolling device slides freely in its casing and has at its lower enda roller 12 which engages the inclined rear face of a gripper jaw 1awhich is piv' oted to its casing at 15, as shown in Fig. 2,

whereby it may be rocked against the cooperating jaw 16 with great forceto grip and hold the stock with the firmness necessary for straining theupper about the last,-for example in the pulling-over operationperformed by pulling-over machines of the type shown in United StatesLetters Patent No. 663,777 granted on the application of Ronald F.McFeely, for which machine the present invention has been especiallydevised.

To withstand the pressure of the pivoted gripper jaw and prevent it fromworking loose under the severe intermittent straining to which it issubjected the jaw 16 requires to be fastened in its casing with specialstrength and security. To this end the easing is provided with edgeplates 20, 20 spaced apart to receive snugly the jaw 16. The inneradjacent faces of the edge plates have alternate grooves and ribs 21, 22as shown in Fig. 3, while the outer edges of jaw 16 are provided withcomplemental ribs and grooves as also appears in that figure. The edgeplates extend below the cross plates or body of the casing, as appearsin Fi 2, and are slightly resilient so that they may be sprung inwardlyto clamp the jaw. The edge plates are also provided with alined recesses24, 25, which taper from the outer toward the inner sides of the plates.The jaw 16 has a transverse recess and through these openings extends aholding member 26. This member has a conical head 27 at one end adaptedto be drawn and wedged into the recess 24. At its opposite end theholding member is screw threaded to receive a locking member 28 formedas a ring or collar having a tapering outer side face for engagementwith the walls of the recess 25 and a screw threaded inner face forengagement with the threaded end of the holding member. The lockingmember is also slotted, as at 80, whereby as it is drawn toward thecontracted inner end of the recess 25 by relative rotary movement of thetwo members it will be compressed by the wedging action of the walls ofthe tapering recess and will be caused to grip or clamp the threadedportion of the holding member and become securely locked thereon. Theresilient edge plates are drawn together by the two members and thereaction causes them to become wedged upon the conical head of theholding member and the tapering outer face of the locking member torestrain relative rotary movement of the two members which would permitthe jaw to work loose. The locking member and the head of the holdingmember may be each formed to be engaged by a tool by which these memberscan be relatively rotated. It is found in practice that grippersconstructed as herein described can be used for several months withoutremoval of parts or loss of efficiency while with the constructionsformerly employed the rigidly mounted jaw would usu* ally begin to workloose in a few days caus ing the grippers to hold and pull the stockimperfectly and occasioning unusual strain and wear upon the pivoted jaw'and its operating mechanism. This made it necessary to renew bothjaws as well as other parts at frequent intervals.

In the modification shown in Fig, 5, the locking member is divided intotwo parts. It may be formed as a single piece and divided by cutting itlongitudinally, removing a portion of the material so that the two partswill be separated by two slots when they are in position of use.

Having explained the nature of this invention and described the bestform thereof at present known to me, I claim as new and desire to secureby Letters Patent of the United States 1. A gripper mechanism comprisinga casing having resilient edge plates, a gripper aw movably connectedwith the casing, a cooperating gripper jaw adapted to be receivedbetween said edge plates, a holding member having a head seated in oneof said edge plates, a locking member seated in a recess in the otheredge plate and having screw-threaded engagement with the holding memberand a tapering side face formed and arranged for wedging engagement withsaid recess, said edge plates being arranged to act yieldingly outwardagainst said members to hold them in locking engagement.

2. A gripper mechanism comprising a casing having resilient edge plates,a gripper jaw having a shank formed to fit into the casing, a holdingmember engaging the shank and arranged in alinement with a taperingrecess in one of said plates, and a compressible locking member locatedin a recess in the other of said plates constructed and arranged to beoperatively engaged with the holding member by force exerted through theresilient edge plates acting outwardly and to be wedged into the recessand clamped thereby upon the holding member.

3. In a mechanism of the class described comprising a casing havingresilient edge plates, a jaw having a shank formed to fit between saidplates, a holding member arranged in alined, oppositely taperingrecesses in said plates and passing through the shank, a tapering headformed on said holding member to fit into one recess, and a splitlocking member having screw threaded engagement with the holding memberand tapered to fit the other recess, said plates being compressed andthereby clamped against said shank and by their reaction serving to holdthe locking member yieldingly into e11 gagement with the screw threadupon the holding member.

4:. In a mechanism of the class described, a casing having resilientedge plates, a jaw fitted into the casing, a holding member extendingthrough the casing and jaw, and a split locking member provided withtapering side faces and having screw threaded en gagement with theholding member and arranged to be compressed through engagement with oneof said resilient plates which plates when drawn together react andcause the locking member to be clamped upon the holding member, saidholding member being formed with a tapering head to fit a similarlyshaped recess in one of said edge plates and shaped and arranged topermit it to be engaged for screwing it into the locking member.

5. In a gripper mechanism, a casing having resilient edge plates, agripper jaw pivotally connected to the casing, a cooperating jaw adaptedto be received between said edge plates, and complemental ribs andgrooves formed on the adjacent faces of said jaw and plates; combinedwith a holding member extending through the edge plates and jaw, and alocking member having screw threaded engagement with the holding memberfor clamping the edge plates upon the jaw, said locking membercomprising a slotted sleeve located wholly within one edge plate andhaving a tapering side face to be wedged into a recess in the adjacentedge plate whereby it is compressed into locking engagement with theholding memher, said wedging engagement being maintained by the reactionof the resilient edge plates against the holding member and lookingmember.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

ALVAH C. SPENCER.

Witnesses ARTHUR L. RUssELL, JAMES R. HODDER.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. C.

